Tropical Fish Forum
Tropical Fish Keeping Help and Advice => Fishtank Filtration and Cycling => Topic started by: daveyng on July 31, 2017, 12:21:26 PM
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Hi all,
I am considering using a 50/50 split of RO/tap water in order to reduce the Hardness of my water. Using the API test kit on my tap water I get a KH of 14 (250.6) and a GH of 19 (340.1). I have a lot of tetras in my tank so I am assuming by halving the KH / GH readings I will be providing them with a more suitable environment to live in.
The Ph averages out at 7.3 as I use CO2 injection for my plants.
I perform water changes daily equating to about 50% of the tank volume a week so I am assuming I won't shock the inhabitants of the tank by doing this.
I also have a lot of shrimp in the tank but I am assuming that a 50% decrease in the hardness of the water should be OK for them.
Any thoughts would be greatly appreciated as to whether this is a good idea or not.
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Using RO is the only way to reduce hardness. The scale is linear, which means that using a 50:50 mix, you will reduce the hardness from 19 to 9.5 and KH from 14 to 7. Check with Seriously Fish to see if a GH of 9.5 is OK for your fish; if not you might need to increase the proportion of RO.
Take the changeover slowly. A small daily water change using the mixture is fine, I would do no more than 10% each time, perhaps less. It will take several water changes to get the tank water to the desired GH but it will get there.
And GH 9.5 or less is fine for the shrimps, I have cherry shrimps in GH 5.
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It’s been nearly six months and my tank water is now composed of 50/50 tap/RO. The fish seem a lot happier and their coloration and growth has improved. Plant growth has also improved with a subsequent reduction in the amount of algae present. All in all a good result.
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@daveyng it's great to hear such positive results. Well done. :cheers:
I know mixing RO with tap water can be a bit of a pain, I use 20% RO in my river tank, but it is work it, as you have shown. :)